GRESHAM, Ore. — Dive teams on Monday recovered a swimmer's body from the Sandy River at Oxbow Park in Gresham. 

The drowning was the second in two weeks at the popular park.

A 15-year-old boy was swimming when he disappeared Monday afternoon, according to a Gresham Fire spokesman. 

His name has not been released.

"I looked down river and saw a young man waving his arms and yelling and then he went under," said Carrie Saums, who was at the river with her son. "I waited for him to reappear and he didn't."

Saums said multiple people jumped into the river to try and find the teen, but couldn't locate him. Within minutes park rangers arrived and were also searching. It took divers over an hour to locate the teen's body.

Capt. Travis Soles with Gresham Fire said the teen wasn't wearing a life jacket.

"The Sandy looks very benign, you can step off a ledge and next thing you know, you're in water that's over your head," he said.

RELATED: Boy, 8, drowns in Sandy River at Gresham's Oxbow Park

An 8-year-old boy drowned in the same area of the Sandy River on July 30.

Authorities are urging swimmers to wear the free life jackets that are offered at the park during the summer.

"One of the biggest things is just getting the message out to people that those resources are there. They're free to use, just getting people to please use them," Soles said.

In June of 2015, 13-year-old Aaron Peters lost his life while swimming at Oxbow Park. A year later, his family returned to donate the life jacket kiosk that's still there today.

"We don't want any family to go through what we did," explained his grandfather, Don Wood. "If one person is saved it's all worth it."

RELATED: Washington mom creates life jacket kiosk where son drowned